The Core Facility for Aged Rodents (CFAR) provides animals and advice for research scientists who wish to use animal models to study the biology of aging, the relationship between aging and disease, or therapeutic approaches that could level to the development of human intervention trials relevant to the independence and health care of the elderly. CFAR is directed by Dr. Richard A. Miller, Professor of Pathology and the Associate Director for Research of the Geriatrics Center. Veterinary consultation is provided by Dr. Robert Dysko, DVM, Assistant Professor of Laboratory Animal Medicine. Aged and control rats and mice are purchased from the NIA Contract Colonies and supplied to recipients of Pepper Center Pilot/Feasibility Grants, to junior faculty scientists who wish to acquire pilot data towards the preparation of an application for OAIC or extramural support, and to established scientists who wish to begin study of a problem in geriatric or gerontology for which they do yet have external support. This facilitated access to old rodents serves to attract developing and established scientists to experimental geriatrics and to facilitate their initial forays in this filed, while at the same time ensuring that they obtain advice from the (Core Director) on matters such as choice of strain and species, appropriate development of a new stocks of genetically heterogeneous mice that have been selectively bred over several generations for improved cellular resistance to homeostatic stresses. The Core will generate these stress-resistant mouse lines by selecting parents, in each generation, whose T lymphocytes are most resistant to brief heat shock or resistant to in vitro treatment with an oxidizing stress, hydrogen peroxide. Mouse lines produced in this way will be used by UM Pepper Center investigators for studies of the connections between cellular homeostasis and intrinsic vulnerability to late life diseases, and will also be made available to researchers at other centers. Through its programs CFAR will continue to provide Pepper Center and other UM researchers with consultation on experimental design, facilitated access to aged rats and mice, and assistance in producing and characterizing new rodent models that are particularly useful for studies of aging and late life disease.